Re: PL/Perl backed crashed during spi_exec_query

Alexey Klyukin <alexk@commandprompt.com> writes:
> One of our customers is running 8.2.14 and use a couple of pl/perl and
> pl/perlu functions written by CMD. Everything worked normally until
> they tried to call one particular pl/perl function from pl/perl via
> spi. It appears that a die call inside the callee just crashes the
> backend.

I think the critical point is actually that you're calling plperl from
plperlu, and we're being careless about restoring the former interpreter
selection on error exit.  The attached patch moves the responsibility
for that into plperl_call_handler, which already has a suitable
PG_TRY block.

            regards, tom lane

Index: plperl.c
===================================================================
RCS file: /cvsroot/pgsql/src/pl/plperl/plperl.c,v
retrieving revision 1.152
diff -c -r1.152 plperl.c
*** plperl.c    28 Sep 2009 17:31:12 -0000    1.152
--- plperl.c    31 Oct 2009 17:27:14 -0000
***************
*** 380,390 ****
      }
  }

!
  static void
  restore_context(bool old_context)
  {
!     if (trusted_context != old_context)
      {
          if (old_context)
              PERL_SET_CONTEXT(plperl_trusted_interp);
--- 380,392 ----
      }
  }

! /*
!  * Restore previous interpreter selection, if two are active
!  */
  static void
  restore_context(bool old_context)
  {
!     if (interp_state == INTERP_BOTH && trusted_context != old_context)
      {
          if (old_context)
              PERL_SET_CONTEXT(plperl_trusted_interp);
***************
*** 870,878 ****
  plperl_call_handler(PG_FUNCTION_ARGS)
  {
      Datum        retval;
!     plperl_call_data *save_call_data;

-     save_call_data = current_call_data;
      PG_TRY();
      {
          if (CALLED_AS_TRIGGER(fcinfo))
--- 872,880 ----
  plperl_call_handler(PG_FUNCTION_ARGS)
  {
      Datum        retval;
!     plperl_call_data *save_call_data = current_call_data;
!     bool        oldcontext = trusted_context;

      PG_TRY();
      {
          if (CALLED_AS_TRIGGER(fcinfo))
***************
*** 883,893 ****
--- 885,897 ----
      PG_CATCH();
      {
          current_call_data = save_call_data;
+         restore_context(oldcontext);
          PG_RE_THROW();
      }
      PG_END_TRY();

      current_call_data = save_call_data;
+     restore_context(oldcontext);
      return retval;
  }

***************
*** 1226,1232 ****
      Datum        retval;
      ReturnSetInfo *rsi;
      SV           *array_ret = NULL;
-     bool        oldcontext = trusted_context;
      ErrorContextCallback pl_error_context;

      /*
--- 1230,1235 ----
***************
*** 1376,1384 ****
      if (array_ret == NULL)
          SvREFCNT_dec(perlret);

-     current_call_data = NULL;
-     restore_context(oldcontext);
-
      return retval;
  }

--- 1379,1384 ----
***************
*** 1391,1397 ****
      Datum        retval;
      SV           *svTD;
      HV           *hvTD;
-     bool        oldcontext = trusted_context;
      ErrorContextCallback pl_error_context;

      /*
--- 1391,1396 ----
***************
*** 1491,1498 ****
      if (perlret)
          SvREFCNT_dec(perlret);

-     current_call_data = NULL;
-     restore_context(oldcontext);
      return retval;
  }

--- 1490,1495 ----